Connector keying system



Jan. 20., 1970 H. E. BARNHART ETAL 3,491,330

CONNECTOR KEYING SYSTEM Filed Sept. 22, 1967 2 Sheets -Sheet l CONNECTOR KEYING SYSTEM Filed Sept. 22, 1967 2 Sheets-Sheet 2 United States Patent 6 3,491,330 CONNECTOR KEYING SYSTEM Harry Edward Barnhart, Hummelstown, and Gilbert Douglas Ferdon, Carlisle, Pa., assiguors to AMP Incorporated, Harrisburg, Pa.

Filed Sept. 22, 1967, Ser. No. 669,739 Int. Cl. H01r 13/64 US. Cl. 339-484 9 Claims ABSTRACT OF THE DISCLOSURE a shank portion on which a bushing, identical to the previons bushing, is mounted. Key and bushing are mounted in opening in the other connector part and locked in one of several positions in the same manner as bushing is mounted in first part.

BACKGROUND OF THE INVENTION The term electrical connector is commonly used to designate devices of the type having two matable parts, each of which contains a plurality of contact terminals so that when the two parts of the connector are engaged with each other, the terminals, and the wires to which they are crimped, are electrically connected to each othe In many types of equipment, a large number of substantially identical electrical connectors are used adjacent to each other and the possibility arises that when several connectors are uncoupled, the uncoupled connector parts will not be re-engaged with their intended mates through carelessness or error. It is, therefore, common practice to provide keying means which prevent the mating of a given connector part with any other connector part excepting its intended mate, see, for example, U.S. Patent No. 3,166,372, 3,206,714, and 3,085,221.

The present invention is directed to the provision of an improved keying means for electrical connectors. It is an object of the invention to provide a keying means composed of a minimum number of parts. A further object is to provide a keying means which provides a large number of keying possibilities. A still further object is to provide a keying means for an environmentally sealed connector which does not detract from the pressure-tight integrity of the connector. A still further object is to eliminate the necessity of removing parts when a keying arrangement is changed.

These and other objects of the invention are achieved in a preferred embodiment comprising a disengageable electrical connector comprising a pair of matable connector parts. A cylindrical bushing having an eccentric opening extending therethrough is mounted in a recess in the mating face of one of the connector parts by means of a screw threaded into the mating face and having a head portion which overlaps the marginal portions of the bushing. This bushing functions as a keyway, its eccentric opening being adapted to receive the end of a keying pin mounted in the mating face of the other connector part. The keying pin itself is cylindrical and is mounted in a cylindrical recess extending into the mating face of the other connector part. The mounting is achieved by means of a bushing, identical to the keying bushing of the first connector part, which is mounted on the shank portion of the keying pin. The keying pin is retained in position on ice the other connector part by means of a screw threaded into the mating face of this other part and having a head portion which overlaps the periphery of the bushing. The cylindrical recesses in the two connector parts which receive the bushings and the keys are advantageously blind recesses, that is, they do not extend through the connector parts, so that the keying system does not provide a continuous path from one side of the connector to the other side. If the connector is peripherally sealed, as is common practice, the pressure-tight integrity of the connector is thus not threatened by the keying system.

In the drawings:

FIGURE 1 is a perspective view showing the two parts of a connector having a keying system in accordance with the invention;

FIGURE 2 is a side view, with parts broken away in the interest of clarity, showing the connector parts of FIGURE 1 in their mated condition, the connector parts being mounted in an equipment housing panel and on a rack respectively;

FIGURE 3 is a fragmentary sectional view of the keying zone of the connector of FIGURE 1 and illustrating the manner in which the keying bushings of the one connector part receive the keying pins of the other connector part; and

FIGURE 4 is a view taken along the lines 4-4 of FIGURE 3.

The invention is herein disclosed in conjunction with a commonly known type of rack and panel connector comprising matable connector parts 2, 4. The part 2 comprises a metallic frame portion including a mounting flange 6 on its mating side and a pair of spaced-apart recesses 8, 10 extending inwardly from its mating side, these recesses being separated by a web portion 12 in which the elements of the keying system are mounted as will be described below. Rearwardly extending housing or shell portions 14, 16 are integral with the frame and are in alignment with the recesses 8, 10, these housings 14, 16 containing inserts 18 (FIGURE 2) of suitable insulating material which have terminal pins 20 mounted therein. The ends 22 of these terminal pins project into the recesses 8, 10 and are adapted to enter contact sockets 20' in the other connector part 4. The terminals are crimped or otherwise secured to the ends of the wires 24 which extend rearwardly from the connector part 2 and are clamped by means of cable clamps 26. These cable clamps are secured by fasteners 28 to the rearward ends of the shell portions 14, 16.

The keying structure of the connector part 2 comprises, in the disclosed embodiment, three side-by-side blind openings 30 which extend inwardly from the mating side of the connector and into the web portion 12 of the frame. These openings are counterbored as shown at 32 to a diameter such that they are adapted to receive cylindrical keying bushings 34, each bushing having a non-circular keying opening 36 extending axially therethrough. In the disclosed embodiment, these openings and the keys adapted to enter these bushings, are semicircular in cross-section as is common practice in the connector art although other irregularly shaped or nonsymmetrical openings might be used.

The keying bushings 34 are clamped in any one of several possible orientations by means of screws 40. These screws are threaded into openings 38 provided between the openings 30 and, in the disclosed embodiment, intersecting the openings 30. The head portions of these screws 40 overlap the peripheries of the bushings 34, a plurality of arcuate recesses 42 being provided on the peripheries of the bushings to receive the screw heads. In the disclosed embodiment, three bushings are mounted in the web portion 12 of the connector frame and two screws 40 are employed, one screw being threaded into the web portion of the frame on each side of the center bushing. The two screws thus function to lock the three keying bushings in position in the web. It will be apparent that the orientation of the center keying bushing as shown in FIGURE 1 can be changed by loosening the two screws 40, rotating the center bushing to its desired orientation, and tightening the screws into the web 12 of the frame. The orientation of the outside bushings, can, of course, be changed by merely loosening the adjacent screw, orientating the bushing in the desired manner, and tightening screw in the frame.

The connector part 4 is similar in many respects, to the connector part 2 and its structural features are therefore, identified with the same reference numerals, differentiated by prime marks, as are used with reference to the part 2. The part 4 is the plug portion of the connector and differs from the part 2 in that shell portions 60, 62 are integral with and extend forwardly from the flange plate 6, these shell portions 60, 62 being adapted to enter the recesses 8, 10 of the part 2 as clearly shown in FIGURE 2.

The keying structure of the part 4 comprises three Separte keys having cylindrical shank portions 52 and each have a half round keying pin portion 54. The flat surface 56 of the pin portion extends rearwardly past the forward end of the shank portion 52 and defines a forwardly facing half round shoulder 58. The keying structure also includes three bushings 34' which are identical to the previously described bushings 34 but which, in this instance, function as locking bushings rather than keying bushings. Bushings 34' are mounted on the keys with their rearward ends against the shoulders 58 of the keys so that the keys can be mounted in the openings 30' with the mounting bushings 34 disposed in the counterbores 32'. Again, the keying structure is held in position by screws 40f threaded into openings provided between the blind openings 30' and having head portions which overlap the bushings 34'.

It will be apparent that after the mounting bushings 34' are assembled to the keys, the keys and the mounting bushings function as a single piece. This arrangement results in substantial economies of manufacture. The keys themselves can be manufactured at little expense since they are produced by simple turning and milling operations. The bushings 34, 34' are identical to each other and are advantageously manufactured by a casting or molding type process, for example, by powdered metallurgy, die casting, precision casting, or injection molding (if they are made of plastic). Processes of this type are best suited for manufacture of the bushings because of the non-circular openings and the arcuate recesses 42 which are provided at one end of each bushing.

It will be apparent from the foregoing description that the assembly of the keys 52 and keyway bushings 34 to the connector frames is a relatively simple process. In the case of the part 2, it is merely necessary to position the keying bushings 34 in the openings 30 and thread the the screws 40 into the threaded openings between the openings 30. In the case of the connector part 4, the keying bushings are placed in the keys with their rearward sides against the shoulders 58. The keys and keying bushings are then mounted in the openings 30', 32' and the fasteners 40 are threaded into the Opening between the blind openings 30. A distinct keying arrangement for a given connector assembly can be achieved by merely imparting a distinctive orientation to the keying members.

In FIGURE 2, the connector part 4 is secured by fasteners 46' to a panel 48 and the connector part 2 is secured by fasteners 46, to a panel 44. In common practice, the panel 44 might be the panel or sidewall of a housing for a given piece of electrical equipment and the member 48 may constitute a rack. Several connectors of the type shown might be mounted in a panel 44 and a corresponding number of connector parts will be mounted in the rack 48 so that when the rack is moved against the panel, the several connectors of the assembly will be engaged with each other.

FIGURE 2 illustrates the manner in which the pressure-tight integrity of the connector is maintained with the instant keying system. The openings 30 in the connector part 2, which receives the key portions of the keying pins, are blind openings as shown and the corresponding openings 30' in the connector part 4 are similarly blind openings. The keying structure does not, therefore, provide a continuous open path from the right to the left in FIGURE 2 and the environmental seal of the connector is maintained. It is understood that connectors of this type will usually be peripherally sealed and that the inserts and contacts will be sealed to maintain a pressure difierential from one side of the connector to the other.

A salient advantage of the invention is that the entire keying structure is achieved with only three separate types of parts, namely, the bushings 34, the keys 52, 54 and the fasteners 40. None of these parts are of an extremely complex shape and assembly of the parts to the connectors is a straightforward and simple operation.

If desired, two additional screws 40 can be used in the connector parts 2, 4 to hold the keying or mounting bushings in position. These additional screws would be threaded into the web portions 12, 12 of the connector frame beside the end bushings, that is, adjacent to the lefthand bushing and adjacent to the right hand bushing in FIGURE 4. The use of four clamping screws of this type rather than two screws has the advantage of providing a redundant clamping arrangement and permitting changing of the orientation of any one of the keys or keying bushings without unclamping the remaining keys and keying bushings. In other words, the end bushings or the end keys can be unclamped, when four clamping screws are used, by removing the screws on each side of the bushing and keying member being changed. The remaining keying bushings and keying pins will not be un clamped because of the presence of the remaining screws.

As previously noted, keying systems in accordance with the invention do not threaten the pressure-tight integrity of a sealed connector by virtue of the blind openings 30 in which the bushings and keys are mounted. It should also be noted that the keying means of both connector parts are serviced from the mating faces of these parts. This feature contributes further to the pressure-tight integrity of the connector and, in addition, permit-s rapid servicing.

It will be understood that the principles of the invention are not limited to the use of semi-circular openings in the bushings 34, 34' and semi-cylindrical keys. It is merely necessary that the openings be such that distinctive keying arangements are achieved when the. bushings are laced in different orientations. An alternative arrangement, for example, would be to provide an 011? center circular opening in each of the bushings and to provide a cylindrical end on the key having a diameter such that it would fit through the bushing opening. The keying end portion of the key would, of course, be 01f center with respect to the axis of the shank portion of the key.

Changes in construction will occur to those skilled in the art and verious apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

What is claimed is:

1. An electrical connector comprising a pair of matable connector parts, said connector having keying means comprising:

a keying bushing having a key-receiving opening extending therethrough.

a mounting bushing, said mounting bushing being identical to said keying bushing,

a keying pin having an elongated keying portion extending through said mounting bushing, and

retaining means for retaining said keying bushing in a recess in the mating face of one of said connector parts and for retaining said mounting bushing and said keying pin in a recess in the other one of said connector parts.

2. Keying means as set forth in claim 1 wherein said bushings have circular cross-sections, said openings in said bushings and said keying portion of said keying pin being half-round.

3. Keying means as set forth in claim 1 wherein said keying pin has a cylindrical shank portion, said mounting bushing being disposed against said shank portion.

4. Keying means as set forth in claim 1 wherein said retaining means comprises screws having radially extending heads, said screws being threadable into the mating sides of said connector parts adjacent to said recesses whereby said heads of said screws overlap said bushings and hold said bushings in said recesses.

5. An electrical connector comprising a pair of matable connector parts, said connector having keying means comprising:

a pair of recesses extending inwardly from the mating faces of said connector parts,

a keying bushing mounted in the recess of one of said connector parts and a mounting bushing mounted in the recess of the other one of said parts, said bushings being identical to each other and having key receiving openings extending therethrough,

retaining means in each of said connector parts for retaining said bushings in said recesses in one of several possible orientations,

a keying pin having a shank portion and an elongated keying portion, said shank portion being disposed in the recess of said other part behind said bushing with said keying portion extending through the keyreceiving opening of said mounting bushing whereby,

said connector parts are distinctively keyed to each ot er.

6. Keying means as set forth in claim 5 wherein said bushings are of circular cross-section, said keying portion of said keying pin having a semi-circular cross-section, said key-receiving openings being half-round openings.

7. Keying means as set forth in claim 5 wherein said retaining means comprises screw means, said screw means being threaded into said mating faces of said connector parts and engaging said bushings.

8. An electrical connector comprising a pair of matable connector parts, conductor having said keying means compnsmg:

a cylindrical bushing, said bushing having an eccentric opening extending therethrough parallel to the axis thereof,

a cylindrical recess extending into the mating face of one of said parts, said bushing being mounted in said recess,

said bushing having a plurality of locking cavities at circumferentially spaced locations around the periphery thereof,

a locking member recess extending into said mating face adjacent to said cylindrical recess,

a locking member in said recess, said locking member having portions extending into one of said locking cavities, whereby said bushing is retained in said cylindrical recess and is locked in one of a plurality of orientations, said eccentric opening being adapted to receive a complementary pin mounted in the other one of said connector parts in an orientation aligning said pin with said opening.

9. Keying means as set forth in claim 8 wherein said locking member comprises a screw, said locking member recess comprising a tapped hole extending into said mating face of said one connector part, said locking member recess being beside said cylindrical recess, said locking cavities comprising arcuate cut outs on one side of said bushing, each of said cut outs being adapted to receive the head of said screw.

References Cited UNITED STATES PATENTS 2,688,123 8/1954 Benham et al. 339-176 2,814,827 12/1957 Snow et al. 154-54 X 2,938,200 5/1960 'Dupree 339-184 X 3,085,221 4/1963 Kelly of a1 339-186 3,206,714 9/1965 Kostich 339-186 FOREIGN PATENTS 961,714 6/ 1964 Great Britain.

RICHARD E. MOORE, Primary Examiner 

